/*
 * Prolific PL2303 USB to serial adaptor driver
 *
 * Copyright (C) 2001-2007 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2003 IBM Corp.
 *
 * Original driver for 2.2.x by anonymous
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License version
 *  2 as published by the Free Software Foundation.
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include "pl2303.h"

/*
 * Version Information
 */
#define DRIVER_DESC "Prolific PL2303 USB to serial adaptor driver"

static int debug;

#define PL2303_CLOSING_WAIT (30*HZ)

static const struct usb_device_id id_table[] = {
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ2)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_DCU11)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ3)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_PHAROS)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_ALDIGA)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_MMX)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_GPRS)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_HCR331)},
    {USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_MOTOROLA)},
    {USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID)},
    {USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID_RSAQ5)},
    {USB_DEVICE(ATEN_VENDOR_ID, ATEN_PRODUCT_ID)},
    {USB_DEVICE(ATEN_VENDOR_ID2, ATEN_PRODUCT_ID)},
    {USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID)},
    {USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID_UCSGT)},
    {USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID)},
    {USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID_2080)},
    {USB_DEVICE(MA620_VENDOR_ID, MA620_PRODUCT_ID)},
    {USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID)},
    {USB_DEVICE(TRIPP_VENDOR_ID, TRIPP_PRODUCT_ID)},
    {USB_DEVICE(RADIOSHACK_VENDOR_ID, RADIOSHACK_PRODUCT_ID)},
    {USB_DEVICE(DCU10_VENDOR_ID, DCU10_PRODUCT_ID)},
    {USB_DEVICE(SITECOM_VENDOR_ID, SITECOM_PRODUCT_ID)},
    {USB_DEVICE(ALCATEL_VENDOR_ID, ALCATEL_PRODUCT_ID)},
    {USB_DEVICE(SAMSUNG_VENDOR_ID, SAMSUNG_PRODUCT_ID)},
    {USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_SX1)},
    {USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X65)},
    {USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X75)},
    {USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_EF81)},
    {USB_DEVICE(BENQ_VENDOR_ID, BENQ_PRODUCT_ID_S81)},  /* Benq/Siemens S81 */
    {USB_DEVICE(SYNTECH_VENDOR_ID, SYNTECH_PRODUCT_ID)},
    {USB_DEVICE(NOKIA_CA42_VENDOR_ID, NOKIA_CA42_PRODUCT_ID)},
    {USB_DEVICE(CA_42_CA42_VENDOR_ID, CA_42_CA42_PRODUCT_ID)},
    {USB_DEVICE(SAGEM_VENDOR_ID, SAGEM_PRODUCT_ID)},
    {USB_DEVICE(LEADTEK_VENDOR_ID, LEADTEK_9531_PRODUCT_ID)},
    {USB_DEVICE(SPEEDDRAGON_VENDOR_ID, SPEEDDRAGON_PRODUCT_ID)},
    {USB_DEVICE(DATAPILOT_U2_VENDOR_ID, DATAPILOT_U2_PRODUCT_ID)},
    {USB_DEVICE(BELKIN_VENDOR_ID, BELKIN_PRODUCT_ID)},
    {USB_DEVICE(ALCOR_VENDOR_ID, ALCOR_PRODUCT_ID)},
    {USB_DEVICE(WS002IN_VENDOR_ID, WS002IN_PRODUCT_ID)},
    {USB_DEVICE(COREGA_VENDOR_ID, COREGA_PRODUCT_ID)},
    {USB_DEVICE(YCCABLE_VENDOR_ID, YCCABLE_PRODUCT_ID)},
    {USB_DEVICE(SUPERIAL_VENDOR_ID, SUPERIAL_PRODUCT_ID)},
    {USB_DEVICE(HP_VENDOR_ID, HP_LD220_PRODUCT_ID)},
    {USB_DEVICE(CRESSI_VENDOR_ID, CRESSI_EDY_PRODUCT_ID)},
    {USB_DEVICE(ZEAGLE_VENDOR_ID, ZEAGLE_N2ITION3_PRODUCT_ID)},
    {USB_DEVICE(SONY_VENDOR_ID, SONY_QN3USB_PRODUCT_ID)},
    {USB_DEVICE(SANWA_VENDOR_ID, SANWA_PRODUCT_ID)},
    {USB_DEVICE(ADLINK_VENDOR_ID, ADLINK_ND6530_PRODUCT_ID)},
    {USB_DEVICE(WINCHIPHEAD_VENDOR_ID, WINCHIPHEAD_USBSER_PRODUCT_ID)},
    {}                          /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_driver pl2303_driver = {
    .name = "pl2303",
    .probe = usb_serial_probe,
    .disconnect = usb_serial_disconnect,
    .id_table = id_table,
    .suspend = usb_serial_suspend,
    .resume = usb_serial_resume,
    .no_dynamic_id = 1,
    .supports_autosuspend = 1,
};

#define SET_LINE_REQUEST_TYPE       0x21
#define SET_LINE_REQUEST        0x20

#define SET_CONTROL_REQUEST_TYPE    0x21
#define SET_CONTROL_REQUEST     0x22
#define CONTROL_DTR         0x01
#define CONTROL_RTS         0x02

#define BREAK_REQUEST_TYPE      0x21
#define BREAK_REQUEST           0x23
#define BREAK_ON            0xffff
#define BREAK_OFF           0x0000

#define GET_LINE_REQUEST_TYPE       0xa1
#define GET_LINE_REQUEST        0x21

#define VENDOR_WRITE_REQUEST_TYPE   0x40
#define VENDOR_WRITE_REQUEST        0x01

#define VENDOR_READ_REQUEST_TYPE    0xc0
#define VENDOR_READ_REQUEST     0x01

#define UART_STATE          0x08
#define UART_STATE_TRANSIENT_MASK   0x74
#define UART_DCD            0x01
#define UART_DSR            0x02
#define UART_BREAK_ERROR        0x04
#define UART_RING           0x08
#define UART_FRAME_ERROR        0x10
#define UART_PARITY_ERROR       0x20
#define UART_OVERRUN_ERROR      0x40
#define UART_CTS            0x80

enum pl2303_type {
    type_0,                     /* don't know the difference between type 0 and */
    type_1,                     /* type 1, until someone from prolific tells us... */
    HX,                         /* HX version of the pl2303 chip */
};

struct pl2303_private {
    spinlock_t lock;
    wait_queue_head_t delta_msr_wait;
    u8 line_control;
    u8 line_status;
    enum pl2303_type type;
};

static int pl2303_vendor_read(__u16 value, __u16 index, struct usb_serial *serial, unsigned char *buf)
{
    int res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                              VENDOR_READ_REQUEST, VENDOR_READ_REQUEST_TYPE,
                              value, index, buf, 1, 100);
    dbg("0x%x:0x%x:0x%x:0x%x  %d - %x", VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, value, index, res, buf[0]);
    return res;
}

static int pl2303_vendor_write(__u16 value, __u16 index, struct usb_serial *serial)
{
    int res = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                              VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
                              value, index, NULL, 0, 100);
    dbg("0x%x:0x%x:0x%x:0x%x  %d", VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, value, index, res);
    return res;
}

static int pl2303_startup(struct usb_serial *serial)
{
    struct pl2303_private *priv;
    enum pl2303_type type = type_0;
    unsigned char *buf;
    int i;

    buf = kmalloc(10, GFP_KERNEL);
    if (buf == NULL)
        return -ENOMEM;

    if (serial->dev->descriptor.bDeviceClass == 0x02)
        type = type_0;
    else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40)
        type = HX;
    else if (serial->dev->descriptor.bDeviceClass == 0x00)
        type = type_1;
    else if (serial->dev->descriptor.bDeviceClass == 0xFF)
        type = type_1;
    dbg("device type: %d", type);

    for (i = 0; i < serial->num_ports; ++i) {
        priv = kzalloc(sizeof(struct pl2303_private), GFP_KERNEL);
        if (!priv)
            goto cleanup;
        spin_lock_init(&priv->lock);
        init_waitqueue_head(&priv->delta_msr_wait);
        priv->type = type;
        usb_set_serial_port_data(serial->port[i], priv);
    }

    pl2303_vendor_read(0x8484, 0, serial, buf);
    pl2303_vendor_write(0x0404, 0, serial);
    pl2303_vendor_read(0x8484, 0, serial, buf);
    pl2303_vendor_read(0x8383, 0, serial, buf);
    pl2303_vendor_read(0x8484, 0, serial, buf);
    pl2303_vendor_write(0x0404, 1, serial);
    pl2303_vendor_read(0x8484, 0, serial, buf);
    pl2303_vendor_read(0x8383, 0, serial, buf);
    pl2303_vendor_write(0, 1, serial);
    pl2303_vendor_write(1, 0, serial);
    if (type == HX)
        pl2303_vendor_write(2, 0x44, serial);
    else
        pl2303_vendor_write(2, 0x24, serial);

    kfree(buf);
    return 0;

  cleanup:
    kfree(buf);
    for (--i; i >= 0; --i) {
        priv = usb_get_serial_port_data(serial->port[i]);
        kfree(priv);
        usb_set_serial_port_data(serial->port[i], NULL);
    }
    return -ENOMEM;
}

static int set_control_lines(struct usb_device *dev, u8 value)
{
    int retval;

    retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                             SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE, value, 0, NULL, 0, 100);
    dbg("%s - value = %d, retval = %d", __func__, value, retval);
    return retval;
}

static void pl2303_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios)
{
    struct usb_serial *serial = port->serial;
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    unsigned long flags;
    unsigned int cflag;
    unsigned char *buf;
    int baud;
    int i;
    u8 control;
    const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
        4800, 7200, 9600, 14400, 19200, 28800, 38400,
        57600, 115200, 230400, 460800, 614400,
        921600, 1228800, 2457600, 3000000, 6000000
    };
    int baud_floor, baud_ceil;
    int k;

    dbg("%s -  port %d", __func__, port->number);

    /* The PL2303 is reported to lose bytes if you change
       serial settings even to the same values as before. Thus
       we actually need to filter in this specific case */

    if (!tty_termios_hw_change(tty->termios, old_termios))
        return;

    cflag = tty->termios->c_cflag;

    buf = kzalloc(7, GFP_KERNEL);
    if (!buf) {
        dev_err(&port->dev, "%s - out of memory.\n", __func__);
        /* Report back no change occurred */
        *tty->termios = *old_termios;
        return;
    }

    i = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                        GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE, 0, 0, buf, 7, 100);
    dbg("0xa1:0x21:0:0  %d - %x %x %x %x %x %x %x", i, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]);

    if (cflag & CSIZE) {
        switch (cflag & CSIZE) {
        case CS5:
            buf[6] = 5;
            break;
        case CS6:
            buf[6] = 6;
            break;
        case CS7:
            buf[6] = 7;
            break;
        default:
        case CS8:
            buf[6] = 8;
            break;
        }
        dbg("%s - data bits = %d", __func__, buf[6]);
    }

    /* For reference buf[0]:buf[3] baud rate value */
    /* NOTE: Only the values defined in baud_sup are supported !
     *       => if unsupported values are set, the PL2303 seems to use
     *          9600 baud (at least my PL2303X always does)
     */
    baud = tty_get_baud_rate(tty);
    dbg("%s - baud requested = %d", __func__, baud);
    if (baud) {
        /* Set baudrate to nearest supported value */
        for (k = 0; k < ARRAY_SIZE(baud_sup); k++) {
            if (baud_sup[k] / baud) {
                baud_ceil = baud_sup[k];
                if (k == 0) {
                    baud = baud_ceil;
                } else {
                    baud_floor = baud_sup[k - 1];
                    if ((baud_ceil % baud)
                        > (baud % baud_floor))
                        baud = baud_floor;
                    else
                        baud = baud_ceil;
                }
                break;
            }
        }
        if (baud > 1228800) {
            /* type_0, type_1 only support up to 1228800 baud */
            if (priv->type != HX)
                baud = 1228800;
            else if (baud > 6000000)
                baud = 6000000;
        }
        dbg("%s - baud set = %d", __func__, baud);
        if (baud <= 115200) {
            buf[0] = baud & 0xff;
            buf[1] = (baud >> 8) & 0xff;
            buf[2] = (baud >> 16) & 0xff;
            buf[3] = (baud >> 24) & 0xff;
        } else {
            /* apparently the formula for higher speeds is:
             * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
             */
            unsigned tmp = 12 * 1000 * 1000 * 32 / baud;
            buf[3] = 0x80;
            buf[2] = 0;
            buf[1] = (tmp >= 256);
            while (tmp >= 256) {
                tmp >>= 2;
                buf[1] <<= 1;
            }
            if (tmp > 256) {
                tmp %= 256;
            }
            buf[0] = tmp;
        }
    }

    /* For reference buf[4]=0 is 1 stop bits */
    /* For reference buf[4]=1 is 1.5 stop bits */
    /* For reference buf[4]=2 is 2 stop bits */
    if (cflag & CSTOPB) {
        /* NOTE: Comply with "real" UARTs / RS232:
         *       use 1.5 instead of 2 stop bits with 5 data bits
         */
        if ((cflag & CSIZE) == CS5) {
            buf[4] = 1;
            dbg("%s - stop bits = 1.5", __func__);
        } else {
            buf[4] = 2;
            dbg("%s - stop bits = 2", __func__);
        }
    } else {
        buf[4] = 0;
        dbg("%s - stop bits = 1", __func__);
    }

    if (cflag & PARENB) {
        /* For reference buf[5]=0 is none parity */
        /* For reference buf[5]=1 is odd parity */
        /* For reference buf[5]=2 is even parity */
        /* For reference buf[5]=3 is mark parity */
        /* For reference buf[5]=4 is space parity */
        if (cflag & PARODD) {
            if (cflag & CMSPAR) {
                buf[5] = 3;
                dbg("%s - parity = mark", __func__);
            } else {
                buf[5] = 1;
                dbg("%s - parity = odd", __func__);
            }
        } else {
            if (cflag & CMSPAR) {
                buf[5] = 4;
                dbg("%s - parity = space", __func__);
            } else {
                buf[5] = 2;
                dbg("%s - parity = even", __func__);
            }
        }
    } else {
        buf[5] = 0;
        dbg("%s - parity = none", __func__);
    }

    i = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE, 0, 0, buf, 7, 100);
    dbg("0x21:0x20:0:0  %d", i);

    /* change control lines if we are switching to or from B0 */
    spin_lock_irqsave(&priv->lock, flags);
    control = priv->line_control;
    if ((cflag & CBAUD) == B0)
        priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
    else
        priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
    if (control != priv->line_control) {
        control = priv->line_control;
        spin_unlock_irqrestore(&priv->lock, flags);
        set_control_lines(serial->dev, control);
    } else {
        spin_unlock_irqrestore(&priv->lock, flags);
    }

    buf[0] = buf[1] = buf[2] = buf[3] = buf[4] = buf[5] = buf[6] = 0;

    i = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                        GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE, 0, 0, buf, 7, 100);
    dbg("0xa1:0x21:0:0  %d - %x %x %x %x %x %x %x", i, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]);

    if (cflag & CRTSCTS) {
        if (priv->type == HX)
            pl2303_vendor_write(0x0, 0x61, serial);
        else
            pl2303_vendor_write(0x0, 0x41, serial);
    } else {
        pl2303_vendor_write(0x0, 0x0, serial);
    }

    /* Save resulting baud rate */
    if (baud)
        tty_encode_baud_rate(tty, baud, baud);

    kfree(buf);
}

static void pl2303_dtr_rts(struct usb_serial_port *port, int on)
{
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    unsigned long flags;
    u8 control;

    spin_lock_irqsave(&priv->lock, flags);
    /* Change DTR and RTS */
    if (on)
        priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
    else
        priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
    control = priv->line_control;
    spin_unlock_irqrestore(&priv->lock, flags);
    set_control_lines(port->serial->dev, control);
}

static void pl2303_close(struct usb_serial_port *port)
{
    dbg("%s - port %d", __func__, port->number);

    usb_serial_generic_close(port);
    usb_kill_urb(port->interrupt_in_urb);
}

static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
{
    struct ktermios tmp_termios;
    struct usb_serial *serial = port->serial;
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    int result;

    dbg("%s -  port %d", __func__, port->number);

    if (priv->type != HX) {
        usb_clear_halt(serial->dev, port->write_urb->pipe);
        usb_clear_halt(serial->dev, port->read_urb->pipe);
    } else {
        /* reset upstream data pipes */
        pl2303_vendor_write(8, 0, serial);
        pl2303_vendor_write(9, 0, serial);
    }

    /* Setup termios */
    if (tty)
        pl2303_set_termios(tty, port, &tmp_termios);

    dbg("%s - submitting read urb", __func__);
    result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
    if (result) {
        pl2303_close(port);
        return -EPROTO;
    }

    dbg("%s - submitting interrupt urb", __func__);
    result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
    if (result) {
        dev_err(&port->dev, "%s - failed submitting interrupt urb," " error %d\n", __func__, result);
        pl2303_close(port);
        return -EPROTO;
    }
    port->port.drain_delay = 256;
    return 0;
}

static int pl2303_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
{
    struct usb_serial_port *port = tty->driver_data;
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    unsigned long flags;
    u8 control;

    if (!usb_get_intfdata(port->serial->interface))
        return -ENODEV;

    spin_lock_irqsave(&priv->lock, flags);
    if (set & TIOCM_RTS)
        priv->line_control |= CONTROL_RTS;
    if (set & TIOCM_DTR)
        priv->line_control |= CONTROL_DTR;
    if (clear & TIOCM_RTS)
        priv->line_control &= ~CONTROL_RTS;
    if (clear & TIOCM_DTR)
        priv->line_control &= ~CONTROL_DTR;
    control = priv->line_control;
    spin_unlock_irqrestore(&priv->lock, flags);

    return set_control_lines(port->serial->dev, control);
}

static int pl2303_tiocmget(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    unsigned long flags;
    unsigned int mcr;
    unsigned int status;
    unsigned int result;

    dbg("%s (%d)", __func__, port->number);

    if (!usb_get_intfdata(port->serial->interface))
        return -ENODEV;

    spin_lock_irqsave(&priv->lock, flags);
    mcr = priv->line_control;
    status = priv->line_status;
    spin_unlock_irqrestore(&priv->lock, flags);

    result = ((mcr & CONTROL_DTR) ? TIOCM_DTR : 0)
        | ((mcr & CONTROL_RTS) ? TIOCM_RTS : 0)
        | ((status & UART_CTS) ? TIOCM_CTS : 0)
        | ((status & UART_DSR) ? TIOCM_DSR : 0)
        | ((status & UART_RING) ? TIOCM_RI : 0)
        | ((status & UART_DCD) ? TIOCM_CD : 0);

    dbg("%s - result = %x", __func__, result);

    return result;
}

static int pl2303_carrier_raised(struct usb_serial_port *port)
{
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    if (priv->line_status & UART_DCD)
        return 1;
    return 0;
}

static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
{
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    unsigned long flags;
    unsigned int prevstatus;
    unsigned int status;
    unsigned int changed;

    spin_lock_irqsave(&priv->lock, flags);
    prevstatus = priv->line_status;
    spin_unlock_irqrestore(&priv->lock, flags);

    while (1) {
        interruptible_sleep_on(&priv->delta_msr_wait);
        /* see if a signal did it */
        if (signal_pending(current))
            return -ERESTARTSYS;

        spin_lock_irqsave(&priv->lock, flags);
        status = priv->line_status;
        spin_unlock_irqrestore(&priv->lock, flags);

        changed = prevstatus ^ status;

        if (((arg & TIOCM_RNG) && (changed & UART_RING)) ||
            ((arg & TIOCM_DSR) && (changed & UART_DSR)) ||
            ((arg & TIOCM_CD) && (changed & UART_DCD)) || ((arg & TIOCM_CTS) && (changed & UART_CTS))) {
            return 0;
        }
        prevstatus = status;
    }
    /* NOTREACHED */
    return 0;
}

static int pl2303_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
{
    struct serial_struct ser;
    struct usb_serial_port *port = tty->driver_data;
    dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);

    switch (cmd) {
    case TIOCGSERIAL:
        memset(&ser, 0, sizeof ser);
        ser.type = PORT_16654;
        ser.line = port->serial->minor;
        ser.port = port->number;
        ser.baud_base = 460800;

        if (copy_to_user((void __user *)arg, &ser, sizeof ser))
            return -EFAULT;

        return 0;

    case TIOCMIWAIT:
        dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
        return wait_modem_info(port, arg);
    default:
        dbg("%s not supported = 0x%04x", __func__, cmd);
        break;
    }
    return -ENOIOCTLCMD;
}

static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
{
    struct usb_serial_port *port = tty->driver_data;
    struct usb_serial *serial = port->serial;
    u16 state;
    int result;

    dbg("%s - port %d", __func__, port->number);

    if (break_state == 0)
        state = BREAK_OFF;
    else
        state = BREAK_ON;
    dbg("%s - turning break %s", __func__, state == BREAK_OFF ? "off" : "on");

    result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                             BREAK_REQUEST, BREAK_REQUEST_TYPE, state, 0, NULL, 0, 100);
    if (result)
        dbg("%s - error sending break = %d", __func__, result);
}

static void pl2303_release(struct usb_serial *serial)
{
    int i;
    struct pl2303_private *priv;

    dbg("%s", __func__);

    for (i = 0; i < serial->num_ports; ++i) {
        priv = usb_get_serial_port_data(serial->port[i]);
        kfree(priv);
    }
}

static void pl2303_update_line_status(struct usb_serial_port *port, unsigned char *data, unsigned int actual_length)
{

    struct pl2303_private *priv = usb_get_serial_port_data(port);
    struct tty_struct *tty;
    unsigned long flags;
    u8 status_idx = UART_STATE;
    u8 length = UART_STATE + 1;
    u8 prev_line_status;
    u16 idv, idp;

    idv = le16_to_cpu(port->serial->dev->descriptor.idVendor);
    idp = le16_to_cpu(port->serial->dev->descriptor.idProduct);

    if (idv == SIEMENS_VENDOR_ID) {
        if (idp == SIEMENS_PRODUCT_ID_X65 || idp == SIEMENS_PRODUCT_ID_SX1 || idp == SIEMENS_PRODUCT_ID_X75) {

            length = 1;
            status_idx = 0;
        }
    }

    if (actual_length < length)
        return;

    /* Save off the uart status for others to look at */
    spin_lock_irqsave(&priv->lock, flags);
    prev_line_status = priv->line_status;
    priv->line_status = data[status_idx];
    spin_unlock_irqrestore(&priv->lock, flags);
    if (priv->line_status & UART_BREAK_ERROR)
        usb_serial_handle_break(port);
    wake_up_interruptible(&priv->delta_msr_wait);

    tty = tty_port_tty_get(&port->port);
    if (!tty)
        return;
    if ((priv->line_status ^ prev_line_status) & UART_DCD)
        usb_serial_handle_dcd_change(port, tty, priv->line_status & UART_DCD);
    tty_kref_put(tty);
}

static void pl2303_read_int_callback(struct urb *urb)
{
    struct usb_serial_port *port = urb->context;
    unsigned char *data = urb->transfer_buffer;
    unsigned int actual_length = urb->actual_length;
    int status = urb->status;
    int retval;

    dbg("%s (%d)", __func__, port->number);

    switch (status) {
    case 0:
        /* success */
        break;
    case -ECONNRESET:
    case -ENOENT:
    case -ESHUTDOWN:
        /* this urb is terminated, clean up */
        dbg("%s - urb shutting down with status: %d", __func__, status);
        return;
    default:
        dbg("%s - nonzero urb status received: %d", __func__, status);
        goto exit;
    }

    usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length, urb->transfer_buffer);

    pl2303_update_line_status(port, data, actual_length);

  exit:
    retval = usb_submit_urb(urb, GFP_ATOMIC);
    if (retval)
        dev_err(&urb->dev->dev, "%s - usb_submit_urb failed with result %d\n", __func__, retval);
}

static void pl2303_process_read_urb(struct urb *urb)
{
    struct usb_serial_port *port = urb->context;
    struct pl2303_private *priv = usb_get_serial_port_data(port);
    struct tty_struct *tty;
    unsigned char *data = urb->transfer_buffer;
    char tty_flag = TTY_NORMAL;
    unsigned long flags;
    u8 line_status;
    int i;

    /* update line status */
    spin_lock_irqsave(&priv->lock, flags);
    line_status = priv->line_status;
    priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
    spin_unlock_irqrestore(&priv->lock, flags);
    wake_up_interruptible(&priv->delta_msr_wait);

    if (!urb->actual_length)
        return;

    tty = tty_port_tty_get(&port->port);
    if (!tty)
        return;

    /* break takes precedence over parity, */
    /* which takes precedence over framing errors */
    if (line_status & UART_BREAK_ERROR)
        tty_flag = TTY_BREAK;
    else if (line_status & UART_PARITY_ERROR)
        tty_flag = TTY_PARITY;
    else if (line_status & UART_FRAME_ERROR)
        tty_flag = TTY_FRAME;
    dbg("%s - tty_flag = %d", __func__, tty_flag);

    /* overrun is special, not associated with a char */
    if (line_status & UART_OVERRUN_ERROR)
        tty_insert_flip_char(tty, 0, TTY_OVERRUN);

    if (port->port.console && port->sysrq) {
        for (i = 0; i < urb->actual_length; ++i)
            if (!usb_serial_handle_sysrq_char(port, data[i]))
                tty_insert_flip_char(tty, data[i], tty_flag);
    } else {
        tty_insert_flip_string_fixed_flag(tty, data, tty_flag, urb->actual_length);
    }

    tty_flip_buffer_push(tty);
    tty_kref_put(tty);
}

/* All of the device info needed for the PL2303 SIO serial converter */
static struct usb_serial_driver pl2303_device = {
    .driver = {
               .owner = THIS_MODULE,
               .name = "pl2303",
               },
    .id_table = id_table,
    .usb_driver = &pl2303_driver,
    .num_ports = 1,
    .bulk_in_size = 256,
    .bulk_out_size = 256,
    .open = pl2303_open,
    .close = pl2303_close,
    .dtr_rts = pl2303_dtr_rts,
    .carrier_raised = pl2303_carrier_raised,
    .ioctl = pl2303_ioctl,
    .break_ctl = pl2303_break_ctl,
    .set_termios = pl2303_set_termios,
    .tiocmget = pl2303_tiocmget,
    .tiocmset = pl2303_tiocmset,
    .process_read_urb = pl2303_process_read_urb,
    .read_int_callback = pl2303_read_int_callback,
    .attach = pl2303_startup,
    .release = pl2303_release,
};

static int __init pl2303_init(void)
{
    int retval;

    retval = usb_serial_register(&pl2303_device);
    if (retval)
        goto failed_usb_serial_register;
    retval = usb_register(&pl2303_driver);
    if (retval)
        goto failed_usb_register;
    printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
    return 0;
  failed_usb_register:
    usb_serial_deregister(&pl2303_device);
  failed_usb_serial_register:
    return retval;
}

static void __exit pl2303_exit(void)
{
    usb_deregister(&pl2303_driver);
    usb_serial_deregister(&pl2303_device);
}

module_init(pl2303_init);
module_exit(pl2303_exit);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
